Mobile telecommunications devices, such as smart phones, have an important role in people life. In order to meet the transmitter power control specifications, in general, the mobile telecommunications devices are required to communicate with the base station and the signals from the mobile telecommunications devices to the base station should have substantially the same power level. If this is not the case, then those signals with greater intensity become on-channel interferers for those signals of reduced intensity.
In general, the gain of the transmitter in the mobile telecommunications device varies with transmit frequency, ambient and die temperature, supply voltage and fabrication process tolerances. However the mobile telecommunications devices are required to change the output power in predetermined step sizes in response to instructions from the base station. Typically the mobile telecommunications devices are expected to be able to make 1 dB changes in output power with 0.5 dB accuracy, and 10 dB step changes in power with 2 dB accuracy, which is also called as an inner loop power control accuracy. The inner loop power control is defined as the relative power difference between the mean power of the original (reference) time slot and the mean power of the target time slot.
Thus, how to improve the transmission power control accuracy of the mobile communication devices becomes a main task.